The Shape of Forests to Come

The Shape of Forests To Come?

At the turn of the last century, nearly one out of every four trees
in the eastern deciduous forests of the United States was an American chestnut.
Averaging 30 meters tall and 2 meters wide, these majestic beauties ranged from
Maine down through the Appalachian mountains and west to Michigan. The
fast-growing and naturally rot-resistant chestnut was an important part of
early American life, its timber widely used for log cabins, posts, and railroad
ties and its abundant nut crop sustaining wildlife as well as livestock.

But within 40
years, a fungal blight had spread throughout the tree's range, felling
virtually every chestnut it touched-some 3.5 billion in all. Brought in by a
New York nurseryman on imported Asian chestnut seedlings that were then sent
all over the country, the blight moved stealthily from tree to tree, entering
through a break in the bark and producing an acid that lowered the tree's pH to
toxic levels. Because it attacks new shoots before they can mature, the fungus
has reduced the once dominant chestnut to little more than a short-lived shrub.

Ever since
chestnut blight was first described at the Bronx Zoo in 1904, scientists have
been struggling to defeat it. One of several efforts is going on in the labs of
Chuck Maynard and Bill Powell, directors of New York State's American Chestnut
Research and Restoration Project. The two scientists have been working since
the late 1980s to genetically engineer a blight-resistant American chestnut. In
the fall of 2004, they made a major breakthrough: shoots finally appeared on a
handful of blight-resistant chestnut embryos in petri dishes in Maynard's lab.
Each of the tiny embryos had a gene from wheat to give it an extra enzyme,
oxalate oxidase, which neutralizes the oxalic acid produced by the blight.

Genetically
engineering the chestnut (or any other plant) involves not only inserting
foreign DNA into its cells but getting the altered, or "transformed," cells to
regenerate into a whole plant. This is particularly difficult with chestnut,
because unlike species such as poplar, it won't regenerate from leaf tissue. So
Maynard and Powell had to work with immature embryo tissue, which is much more
difficult. Unlike the natural transformation a tree seed undergoes in the
forest, the method plant biotechnologists use-somatic embryogenesis-is a
multi-step, highly sterile, precision operation. It demands vigilant
monitoring, special chemical solutions, and filtering equipment to prevent
contamination of the fledgling embryos and coax them into seedlings that can
survive outside the lab.

Barring
unforeseen problems, Maynard and Powell hope to have potted plants by this
summer, to begin field tests in either the fall or spring, and then to do three
years of field trials. If all goes smoothly, they expect to begin deploying
genetically modified (GM) American chestnut seedlings to forests in the United
States in about four years. Because their goal is to reestablish this tree in
its natural range, the two scientists want the Animal and Plant Health
Inspection Service (APHIS), the branch of the U.S. agriculture department that
regulates biotech plants, to allow their transgenic chestnut genes to spread as
far and mix with as many chestnut stump sprouts as possible. In fact, they
propose that transgenes from any GM tree in a forest restoration or disease
eradication project be granted such regulatory freedom. (In addition to the
chestnut, they've engineered transgenic elm seedlings to fight Dutch elm
disease, field tested GM hybrid poplars, and identified other pathogens that
affect butternut, white pine, beech, dogwood, and oak.)

But it's
impossible to know in advance what kind of impacts transgenic trees will have
on wild forests. Maynard and Powell see only a minuscule risk of ecological
disruption (if any) with their GM chestnut, since it will contain just three or
four foreign genes-the target trait plus a few others needed for the desired
transformation. The scientists say greater unknowns exist with the conventionally
bred and backcrossed American chestnut, which draws one-sixteenth of its genes
from its naturally blight-resistant relative, the Chinese chestnut.

Others,
however, aren't convinced that ecological safety depends merely on how many
foreign genes a transgenic organism contains, particularly when GM organisms
may include genes that didn't evolve together and have never existed in nature.
Faith Thompson Campbell, a former advocate with American Lands who is now at
The Nature Conservancy, summarized the views of many skeptics in her 2000
report "Genetically Engineered Trees: Questions Without Answers." Here, she
warns that GM trees planted near large populations of wild relatives will
inevitably spread their genes and alter the genomes (the full complement of an
organism's genetic material) of wild trees, including those in national parks,
wilderness areas, and other reserves. Since the introduced genes have not
evolved with those of wild trees, they could have unpredicted impacts and be
unstable over the long lifespan of a tree. Moreover, trees modified to exhibit
desired traits such as drought or pest resistance may be able to outcompete
native vegetation and spread as weeds in wild forests. As a result, Thompson
Campbell argues, changing the genetic codes of some trees could have
significant impacts on the ecological functioning of an entire forest.

At the same
time, large gaps in scientific understanding of forest ecosystems make it
difficult to predict, or even recognize, the wider impact of engineered trees.
Two leading proponents of GM trees reaffirmed this at a biotech tree conference
in North Carolina in November 2004. After describing the monumental effort of
sequencing the genes in the Nisqually poplar, Jerry Tuskan, a senior scientist
at the Department of Energy's Oak Ridge National Laboratory, said, "So I stand
here looking at the poplar genome data set and realize we know nothing about
how trees grow." Later, on a panel discussing current knowledge gaps, Ron
Sederoff, co-director of the Forest Biotechnology Group at North Carolina State
University-and one of the most outspoken advocates for GM trees-admitted, "We
don't know a few important things.... We don't know what a genome really is.... We
don't know how many genes there are, because we don't know what a gene really
is. We don't know the extent of something that I call epigenomics-the
non-genetic changes that occur in genomes that are unstable."

Plant
pathologist Doug Gurian-Sherman, a former scientist with the U.S. Environmental
Protection Agency who now works at the International Center for Technology
Assessment, explains some of the complexities. He notes that trees, and plants
in general, produce an array of compounds whose primary purpose appears to be
warding off pathogens and harmful insects. This occurs through a sophisticated
system of biochemical and metabolic pathways-functions that aren't fully
understood by plant physiologists who specialize in the subject, let alone by
the molecular biologists manipulating tree DNA. "As biologists, we have to be a
little humble and say ‘Look, these are complex interactions,'" Gurian-Sherman
says. "Frankly, we can't predict how they're all going to play out."

Like many,
Gurian-Sherman sees the appeal of wanting to restore the dominant tree in
eastern forests. He says there's even a reasonable chance that Maynard and
Powell's transgenic chestnuts won't cause harm in the wild because the target
trait-the enzyme that neutralizes oxalic acid-is not as obviously disruptive
as, say, inserting an insecticide like Bacillus thuringiensis (Bt), which could
kill large numbers of non-target insects. But the only way to really know GM
chestnuts won't cause harm, he notes, is to study in a controlled setting how
different forest animals, birds, insects, and microorganisms respond over
several generations of the tree's lifetime. Different growth cycles in the
tree, environmental and climatic changes, and numerous other factors could
trigger unintended impacts over time. Avoiding such mistakes is important
because, once released, it won't be possible to recall the GM chestnut trees
back to the lab.

So far,
however, there's no indication that federal regulators will require the GM
chestnut to undergo the kind of full environmental risk assessment
Gurian-Sherman is calling for, and he's concerned this will set a dangerous
precedent. He also predicts the biotech industry will use the example of the
transgenic chestnut to say that all genetically engineered trees are safe. "But
different transgenes will have very different impacts," he says. "It's like
doing a crash test with a Volvo that passed with flying colors. That tells you
nothing about how a little Kia will perform in the same test."

Gurian-Sherman's
suspicions appear well placed. At the North Carolina biotech meeting in November,
forest industry veteran Scott Wallinger, who recently retired from paper giant
MeadWestvaco, was one of many speakers who acknowledged the public relations
value of the blight-resistant GM chestnut: "This pathway can begin to provide
the public with a much more personal sense of the value of forest biotechnology
and receptivity to other aspects of genetic engineering."

Skinhead
Earth?

Like their colleagues in agriculture, proponents of forestry biotech
use the rationale of looming scarcity and environmental preservation to argue
their cause. In a 2000 Foreign Affairs article widely quoted in forestry
circles, David Victor and Jesse Ausubel offer two visions for the future. In
one, "quaint and inefficient agriculture and forestry" lead to a "Skinhead
Earth" scenario, where the planet's forest cover shrinks by 200 million
hectares by 2050, and lumberjacks regularly shave 40 percent of what remains.
Alternatively, "efficient farmers and foresters" who grow "more food and fiber
in ever-smaller areas" herald a "Great Restoration" that adds 200 million
hectares of forest by 2050 and requires cutting only 12 percent of the world's
woodlands to meet global demand for forest products.

Genetically
engineered trees grown in intensively managed plantations, or "fast forests,"
fit into the latter scenario. Today, forest plantations produce one quarter of
the world's industrial wood. Though still a tiny percentage of the Earth's
nearly 4 billion hectares of forests, they are expanding rapidly, especially in
Asia and South America. According to the United Nations Food and Agriculture
Organization, between 1990 and 2000, plantations increased 51 percent from 124
million hectares to 187 million hectares. At current rates of planting, they
are projected to produce one billion cubic meters of wood-half of the world's
supply-by 2050.

The American
South, the nation's wood basket since the late 1980s, produces 15 percent of
the world's pulp and paper products, primarily from 13 million hectares of
intensively managed loblolly pine plantations. Timber companies have invested
up to $1 billion for each of the pulp and paper mills that pump out reams of
paper, newsprint, and cardboard, says Conner Bailey, a rural sociologist at
Auburn University who studies the timber industry. Yet mounting competition
from low-cost pulp and paper producers in places like Indonesia and Brazil is
putting these investments at risk, because the mills aren't easily converted to
other uses. The industry's solution to safeguarding their profits? Increase
efficiency through technological innovation, including by genetically
engineering the raw material.

High on the
pulp and paper industry's wish-list is a tree with reduced lignin, the cellular
glue that holds wood fibers together and gives a tree its structure. Lignin,
which accounts for about 30 percent of the dry weight of a tree trunk, is good
for lumber, but removing it for papermaking is messy, toxic, and costly.
Engineering trees with less lignin could mean significant cost savings for
paper manufacturers.

Unresolved
issues remain, however. Former MeadWestvaco executive Wallinger points out that
in the U.S. South, paper mills buy about one-third of their fiber from private
forest owners who typically grow some trees for pulp and others for saw timber.
Gene flow from low-lignin transgenics could alter the timber trees, which are
about four times as valuable. On the manufacturing side, separate processing
lines for the two would have to be set up, requiring yet more capital
investment. Meanwhile, studies have linked high lignin content with greater
resistance to diseases and pests, suggesting that weakening this trait could
make trees more vulnerable to these threats.

Big
Stumps of Wood

Scientists are testing genetically engineered trees with several other
traits of interest to forestry companies, including faster growth, tolerance to
drought and salty environments, herbicide resistance, insect resistance
(primarily Bt), and altered flowering. More complicated-and more financially
risky-traits include straighter-grained and knotless pines, and cold-tolerant
eucalyptus trees for plantations in the United States and other places too cold
for eucalypts. One of the stranger visions comes from University of Washington
molecular biologist Toby Bradshaw, a leading proponent of transgenic trees, who
told Science in 2002 that trees could one day be "rearchitected" to be,
basically, big stumps of wood-"short, wide, almost branchless organisms without
extensive root systems" that could pack super-intensive tree plantations.

Experience
with GM crops-from Bt corn to Roundup Ready canola-has proven that transgenes
spread widely in the environment. But key differences between annual
agricultural crops and forest trees make the risks of transgenic contamination
in forests even greater. Because of the size of trees, the amount of seeds and
pollen they produce, and the updrafts that occur in forests and tree
plantations, the scale of gene flow among trees is "unprecedented" compared to
food crops, says Claire Williams, a forest geneticist at Duke University. And
while most annual agricultural crops cannot survive outside the comparatively
simple ecosystem of a farm field, long-lived trees are designed to exist in
complex, but poorly understood, wild environments.

Tom Whitham,
an ecologist at Northern Arizona University, works with other scientists to
document how certain genetic traits affect relationships between trees,
understory plants, insects, animals, and micro-organisms. His research shows
that genes in individual organisms and populations have "extended
phenotypes"-identifiable effects on an ecosystem beyond the organism. Extended
phenotypes are particularly important when they occur in dominant plants and
keystone species like trees, he says, because they can affect as many as a
thousand other species. In addition, traits that may be beneficial under one
set of circumstances can become problematic under another. For example, in
ongoing research of pinyon pine ecology, Whitman's team discovered that some of
the trees are naturally resistant to the stem-boring moth, an insect that eats
away at the woody stems. In the first 19 years of their study, the
insect-resistant trees did much better. But in a record drought in the
twentieth year, about 70 percent of the insect-resistant trees died, while 80
percent of the non-resistant trees survived. "That was a real shock," he says.

In a survey
of hundreds of published studies, Whitham found that the more factors a study
considered, the greater the likelihood of observing such "ecosystem reversals."
He says this is important because changes (including those likely to be induced
by genetic engineering) that ignore interactions over time, space, and numbers
of species run a high risk of having the opposite effect from what was intended.

Tree
biotechnologists acknowledge that GM trees could threaten native forests. But
they believe they can solve the problem by making the seeds and pollen sterile,
so they cannot reproduce and spread transgenic traits. Yet there is no
guarantee a transgenic tree will remain sterile throughout its life. Moreover,
many trees, like the American chestnut, also reproduce by sending suckers up
from their roots or by re-growing from broken twigs.

Future
Prospects

So far, GM trees have not been released commercially, except in
China, where more than one million Bt poplars are reported to have been planted
nationwide. The reforestation is part of the Chinese government's plan to cover
44 million hectares with trees by 2012 to prevent flooding, droughts, and the
spread of deserts. Meanwhile, hundreds of field trials have taken place in the
open environment-mostly in the United States, but also in Canada, Europe, New
Zealand, Japan, and a handful of other countries-though researchers in most
places are currently required to cut down any GM trees before they flower.

Despite their
enthusiasm, tree biotechnologists face some challenges before transgenic trees
march across the American landscape. The large investments required over long
periods are a tough sell in a world where time is money. (Forestry veteran
Scott Wallinger laments that the first biotech tree products from 20 years ago
are still being tested.) Changing trends in timberland ownership are adding
further uncertainty. Investment companies are buying up large tracts of land
from forestry corporations, and their commitment to the technology, or even how
long they'll own the land, is unknown. After witnessing public resistance to
agricultural biotech, GM tree proponents are also very concerned about how the public
will react to their plans.

Nevertheless,
GM forestry is likely to get a substantial boost from a decision in December
2003 by parties to the UN Framework Convention on Climate Change, the
international treaty aimed at reducing emissions of carbon dioxide and other
greenhouse gases that contribute to global warming. Under the convention's
Kyoto Protocol, which sets specific targets for these reductions and entered
into force this February, countries will be allowed to offset their carbon
emissions by planting tracts of GM trees, which would absorb and store
atmospheric carbon. According to Heidi Bachram of the Transnational Institute,
millions of dollars in public subsidies are being used as incentives to
establish such plantations, despite the questionable benefit of establishing
them in lieu of forcing polluters to reduce their emissions up front. Moreover, in order to keep the stored carbon from entering the
atmosphere, the plantations would have to be prevented from burning, being
destroyed by pests or diseases, or being cut down.

Meanwhile,
the USDA's APHIS, which oversees field tests and grants permits for the
unrestricted commercial release of transgenic plants, is revamping its biotech
regulations. In 2003, a National Academy of Sciences study faulted the agency
for not having the resources, staff, or expertise to adequately assess the
environmental impact of GM releases, especially as the technology progresses.
According to Lee Handley, who works for the Risk Assessment Branch of APHIS's
Biotechnology Regulatory Services, the agency is considering scrapping the
current system of notifications and permits in favor of a new multi-tiered
system, where the regulations for a particular GM plant (including both trees
and crops) would depend on the environmental risk the agency thought it posed.
For example, insect resistant trees might be required to be sterile, while GM
trees with other traits might not. APHIS is also considering adding a category
of "conditional release" that would require additional data to be collected on
a given planting over time.

The proposed
rules are expected sometime in 2005, and final regulations will come out
following the agency's review of comments. Handley, a forest industry veteran,
has strongly urged industry members to make their voices heard by participating
in the public comment period. At the North Carolina conference he warned
participants that GM trees "are definitely on the radar screen" of
environmental groups, which are "very well organized and sophisticated"-which
suggests just how nervous biotech tree proponents are, since most mainstream
environmental groups have not addressed this issue, and very few people know
genetically engineered trees even exist.

In their
Foreign Affairs piece, David Victor and Jesse Ausubel remind us that "forests
matter": they host much of the planet's biodiversity, protect watersheds and
provide clean drinking water, and remove carbon dioxide from the atmosphere.
"Forests count-not just for their ecological and industrial services but also
for the sake of order and beauty," they write. A key question as we consider
genetically engineered forests is what to do to preserve wild forests, and who
gets to decide.

Karen Charman is an independent
investigative journalist specializing in environmental issues. She is also the
managing editor of the journal Capitalism Nature Socialism.